Not obsolete, though far from optimal for all-around use.
Inside 20 yards against only a few opponents, the shotgun can wreak havoc in a trained user's hands. In an area where you may rapidly change ranges from 1 yard to 200 and face multiple moving opponents, the rifle reigns supreme as we've known since the 1800s.
"And Shepherds we shall be. For thee, my Lord for thee. Power hath descended forth from thy hand, that our feet may swiftly carry out thy command. So we shall flow a river forth to thee and teeming with souls shall it ever be. In nomine Patris, et fili, et Spiritus Sancti. Amen."